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WiP: age-withdraw implementation, part 3/n

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- retrieval of previous commitment
- validity check of all denominations
- comparison of accumulated values and fees with commited value and fee.
- update gana
This commit is contained in:
Özgür Kesim 2023-03-06 20:42:48 +01:00
parent af1001bc42
commit 262b470878
Signed by: oec
GPG Key ID: 3D76A56D79EDD9D7
2 changed files with 299 additions and 59 deletions
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2
contrib/gana

@ -1 +1 @@
Subproject commit 214bc664476333a2c042ae57911558d1325e725f
Subproject commit 02132ededc12a0a1cfd81f0ca76c384304e15259

356
src/exchange/taler-exchange-httpd_age-withdraw_reveal.c
View File

@ -42,7 +42,7 @@ struct AgeRevealContext
/**
* Public key of the reserve for with the age-withdraw commitment was
* originally made. This parameter is provided by the client again
* during the call to reveal in order to save a database-lookup .
* during the call to reveal in order to save a database-lookup.
*/
struct TALER_ReservePublicKeyP reserve_pub;
@ -52,20 +52,41 @@ struct AgeRevealContext
uint32_t num_coins;
/**
* TODO:oec num_coins denoms
* #num_coins hashes of the denominations from which the coins are withdrawn.
* Those must support age restriction.
*/
struct TALER_DenominationHashP *denoms_h;
/**
* TODO:oec num_coins blinded coins
* #num_coins denomination keys, found in the system, according to denoms_h;
*/
struct TEH_DenominationKey *denom_keys;
/**
* #num_coins hases of blinded coins.
*/
struct TALER_BlindedCoinHashP *coin_evs;
/**
* TODO:oec num_coins*(kappa - 1) disclosed coins
* Total sum of all denominations' values
**/
struct TALER_Amount total_amount;
/**
* Total sum of all denominations' fees
*/
struct TALER_Amount total_fee;
/**
* #num_coins*(kappa - 1) disclosed coins.
*/
struct GNUNET_CRYPTO_EddsaPrivateKey *disclosed_coins;
/**
* The data from the original age-withdraw. Will be retrieved from
* the DB via @a ach.
*/
struct TALER_EXCHANGEDB_AgeWithdrawCommitment commitment;
};
/**
@ -75,30 +96,35 @@ void
age_reveal_context_free (struct AgeRevealContext *actx)
{
GNUNET_free (actx->denoms_h);
GNUNET_free (actx->denom_keys);
GNUNET_free (actx->coin_evs);
GNUNET_free (actx->disclosed_coins);
}
/**
* Handle a "/age-withdraw/$ACH/reveal request. Parses the given JSON
* ... TODO:oec:description
* Parse the json body of an '/age-withdraw/$ACH/reveal' request. It extracts
* the denomination hashes, blinded coins and disclosed coins and allocates
* memory for those.
*
* @param connection The MHD connection to handle
* @param actx The context of the operation, only partially built at call time
* @param j_denoms_h Array of hashes of the denominations for the withdrawal, in JSON format
* @param j_coin_evs The blinded envelopes in JSON format for the coins that are not revealed and will be signed on success
* @param j_disclosed_coins The n*(kappa-1) disclosed coins' private keys in JSON format, from which all other attributes (age restriction, blinding, nonce) will be derived from
* @param[out] actx The context of the operation, only partially built at call time
* @param[out] mhd_mret The result if a reply is queued for MHD
* @return true on success, false on failure, with a reply already queued for MHD.
*/
MHD_RESULT
handle_age_withdraw_reveal_json (
static enum GNUNET_GenericReturnValue
parse_age_withdraw_reveal_json (
struct MHD_Connection *connection,
struct AgeRevealContext *actx,
const json_t *j_denoms_h,
const json_t *j_coin_evs,
const json_t *j_disclosed_coins)
const json_t *j_disclosed_coins,
struct AgeRevealContext *actx,
MHD_RESULT *mhd_ret)
{
MHD_RESULT mhd_ret = MHD_NO;
enum GNUNET_GenericReturnValue result = GNUNET_SYSERR;
/* Verify JSON-structure consistency */
{
@ -129,10 +155,13 @@ handle_age_withdraw_reveal_json (
TALER_CNC_KAPPA_MINUS_ONE_STR " times the size of denoms_h";
if (NULL != error)
return TALER_MHD_reply_with_error (connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_GENERIC_PARAMETER_MALFORMED,
error);
{
*mhd_ret = TALER_MHD_reply_with_error (connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_GENERIC_PARAMETER_MALFORMED,
error);
return GNUNET_SYSERR;
}
}
/* Continue parsing the parts */
@ -158,11 +187,11 @@ handle_age_withdraw_reveal_json (
sizeof(msg),
"couldn't parse entry no. %d in array denoms_h",
idx + 1);
mhd_ret = TALER_MHD_reply_with_error (connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_GENERIC_PARAMETER_MALFORMED,
msg);
goto CLEANUP;
*mhd_ret = TALER_MHD_reply_with_error (connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_GENERIC_PARAMETER_MALFORMED,
msg);
goto EXIT;
}
};
@ -184,11 +213,11 @@ handle_age_withdraw_reveal_json (
sizeof(msg),
"couldn't parse entry no. %d in array coin_evs",
idx + 1);
mhd_ret = TALER_MHD_reply_with_error (connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_GENERIC_PARAMETER_MALFORMED,
msg);
goto CLEANUP;
*mhd_ret = TALER_MHD_reply_with_error (connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_GENERIC_PARAMETER_MALFORMED,
msg);
goto EXIT;
}
};
@ -211,28 +240,211 @@ handle_age_withdraw_reveal_json (
sizeof(msg),
"couldn't parse entry no. %d in array disclosed_coins",
idx + 1);
mhd_ret = TALER_MHD_reply_with_error (connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_GENERIC_PARAMETER_MALFORMED,
msg);
goto CLEANUP;
*mhd_ret = TALER_MHD_reply_with_error (connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_GENERIC_PARAMETER_MALFORMED,
msg);
goto EXIT;
}
};
}
/* TODO:oec: find commitment */
/* TODO:oec: check validity of denoms */
/* TODO:oec: check amount total against denoms */
/* TODO:oec: compute the disclosed blinded coins */
/* TODO:oec: generate h_commitment_comp */
/* TODO:oec: compare h_commitment_comp against h_commitment */
/* TODO:oec: sign the coins */
/* TODO:oec: send response */
result = GNUNET_OK;
*mhd_ret = MHD_YES;
CLEANUP:
age_reveal_context_free (actx);
return mhd_ret;
EXIT:
return result;
}
/**
* Check if the request belongs to an existing age-withdraw request.
* If so, sets the age_withdraw object with the request data.
* Otherwise, it queues an appropriate MHD response.
*
* @param connection The HTTP connection to the client
* @param h_commitment Original commitment value sent with the age-withdraw request
* @param reserve_pub Reserve public key used in the original age-withdraw request
* @param[out] commitment Data from the original age-withdraw request
* @param[out] result In the error cases, a response will be queued with MHD and this will be the result.
* @return GNUNET_OK if the withdraw request has been found,
* GNUNET_SYSERROR if we did not find the request in the DB
*/
static enum GNUNET_GenericReturnValue
retrieve_original_commitment (
struct MHD_Connection *connection,
const struct TALER_AgeWithdrawCommitmentHashP *h_commitment,
const struct TALER_ReservePublicKeyP *reserve_pub,
struct TALER_EXCHANGEDB_AgeWithdrawCommitment *commitment,
MHD_RESULT *result)
{
enum GNUNET_DB_QueryStatus qs;
qs = TEH_plugin->get_age_withdraw_info (TEH_plugin->cls,
reserve_pub,
h_commitment,
commitment);
switch (qs)
{
case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
return GNUNET_OK; /* Only happy case */
case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
*result = TALER_MHD_reply_with_error (connection,
MHD_HTTP_NOT_FOUND,
TALER_EC_EXCHANGE_AGE_WITHDRAW_COMMITMENT_UNKNOWN,
NULL);
break;
case GNUNET_DB_STATUS_HARD_ERROR:
*result = TALER_MHD_reply_with_error (connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_GENERIC_DB_FETCH_FAILED,
"get_age_withdraw_info");
break;
case GNUNET_DB_STATUS_SOFT_ERROR:
/* FIXME: Do we queue a result in this case or retry? */
default:
GNUNET_break (0); /* should be impossible */
*result = TALER_MHD_reply_with_error (connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE,
NULL);
}
return GNUNET_SYSERR;
}
/**
* Check if the given array of hashes of denomination_keys a) belong
* to valid denominations and b) those are marked as age restricted.
*
* @param connection The HTTP connection to the client
* @param len The lengths of the array @a denoms_h
* @param denoms_h array of hashes of denomination public keys
* @param[out] dks On success, will be filled with the denomination keys. Caller must deallocate.
* @param amount_with_fee The commited amount including fees
* @param[out] total_sum On success, will contain the total sum of all denominations
* @param[out] total_fee On success, will contain the total sum of all fees
* @param[out] result In the error cases, a response will be queued with MHD and this will be the result.
* @return GNUNET_OK if the denominations are valid and support age-restriction
* GNUNET_SYSERR otherwise
*/
static enum GNUNET_GenericReturnValue
all_denominations_valid (
struct MHD_Connection *connection,
uint32_t len,
const struct TALER_DenominationHashP *denoms_h,
struct TEH_DenominationKey **dks,
const struct TALER_Amount *amount_with_fee,
struct TALER_Amount *total_amount,
struct TALER_Amount *total_fee,
MHD_RESULT *result)
{
struct TEH_KeyStateHandle *ksh;
GNUNET_assert (*dks == NULL);
ksh = TEH_keys_get_state ();
if (NULL == ksh)
{
*result = TALER_MHD_reply_with_error (connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_EXCHANGE_GENERIC_KEYS_MISSING,
NULL);
return GNUNET_SYSERR;
}
*dks = GNUNET_new_array (len, struct TEH_DenominationKey);
TALER_amount_set_zero (TEH_currency, total_amount);
TALER_amount_set_zero (TEH_currency, total_fee);
for (uint32_t i = 0; i < len; i++)
{
dks[i] = TEH_keys_denomination_by_hash2 (
ksh,
&denoms_h[i],
connection,
result);
/* Does the denomination exist? */
if (NULL == dks[i])
{
GNUNET_assert (result != NULL);
/* Note: a HTTP-response has been queued and result has been set by
* TEH_keys_denominations_by_hash2 */
return GNUNET_SYSERR;
}
/* Does the denomation support age restriction ? */
if (0 == dks[i]->denom_pub.age_mask.bits)
{
char msg[256] = {0};
GNUNET_snprintf (msg,
sizeof(msg),
"denomination key no. %d does not support age restriction",
i + 1);
*result = TALER_MHD_reply_with_error (connection,
MHD_HTTP_BAD_REQUEST,
TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN,
msg);
return GNUNET_SYSERR;
}
/* Accumulate the values */
if (0 > TALER_amount_add (
total_amount,
total_amount,
&dks[i]->meta.value))
{
GNUNET_break (0);
*result = TALER_MHD_reply_with_error (connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_EXCHANGE_AGE_WITHDRAW_AMOUNT_OVERFLOW,
"amount");
return GNUNET_SYSERR;
}
/* Accumulate the withdraw fees */
if (0 > TALER_amount_add (
total_fee,
total_fee,
&dks[i]->meta.fees.withdraw))
{
GNUNET_break (0);
*result = TALER_MHD_reply_with_error (connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
TALER_EC_EXCHANGE_AGE_WITHDRAW_AMOUNT_OVERFLOW,
"fee");
return GNUNET_SYSERR;
}
}
/* Compare the commited amount against the totals */
{
struct TALER_Amount sum;
TALER_amount_set_zero (TEH_currency, &sum);
GNUNET_assert (0 < TALER_amount_add (
&sum,
total_amount,
total_fee));
if (0 != TALER_amount_cmp (&sum, amount_with_fee))
{
GNUNET_break (0);
*result = TALER_MHD_reply_with_ec (connection,
TALER_EC_EXCHANGE_AGE_WITHDRAW_AMOUNT_INCORRECT,
NULL);
return GNUNET_SYSERR;
}
}
return GNUNET_OK;
}
@ -242,6 +454,8 @@ TEH_handler_age_withdraw_reveal (
const struct TALER_AgeWithdrawCommitmentHashP *ach,
const json_t *root)
{
MHD_RESULT result = MHD_NO;
enum GNUNET_GenericReturnValue ret = GNUNET_SYSERR;
struct AgeRevealContext actx = {0};
json_t *j_denoms_h;
json_t *j_coin_evs;
@ -258,33 +472,59 @@ TEH_handler_age_withdraw_reveal (
/* Parse JSON body*/
{
enum GNUNET_GenericReturnValue res;
res = TALER_MHD_parse_json_data (rc->connection,
ret = TALER_MHD_parse_json_data (rc->connection,
root,
spec);
if (GNUNET_OK != res)
if (GNUNET_OK != ret)
{
GNUNET_break_op (0);
return (GNUNET_SYSERR == res) ? MHD_NO : MHD_YES;
return (GNUNET_SYSERR == ret) ? MHD_NO : MHD_YES;
}
}
/* handle reveal request */
{
MHD_RESULT res;
do {
/* Extract denominations, blinded and disclosed coins */
if (GNUNET_OK != parse_age_withdraw_reveal_json (rc->connection,
j_denoms_h,
j_coin_evs,
j_disclosed_coins,
&actx,
&result))
break;
res = handle_age_withdraw_reveal_json (rc->connection,
&actx,
j_denoms_h,
j_coin_evs,
j_disclosed_coins);
/* Find original commitment */
if (GNUNET_OK != retrieve_original_commitment (rc->connection,
&actx.ach,
&actx.reserve_pub,
&actx.commitment,
&result))
break;
GNUNET_JSON_parse_free (spec);
return res;
}
/* Ensure validity of denoms and the sum of amounts and fees */
if (GNUNET_OK != all_denominations_valid (
rc->connection,
actx.num_coins,
actx.denoms_h,
&actx.denom_keys,
&actx.commitment.amount_with_fee,
&actx.total_amount,
&actx.total_fee,
&result))
break;
} while(0);
/* TODO:oec: compute the disclosed blinded coins */
/* TODO:oec: generate h_commitment_comp */
/* TODO:oec: compare h_commitment_comp against h_commitment */
/* TODO:oec: sign the coins */
/* TODO:oec: send response */
age_reveal_context_free (&actx);
GNUNET_JSON_parse_free (spec);
return result;
}